Spray gun



March 13, 1945 H. A: ROSELUND 2,371,546

SPRAY GUN Fj.l ed March 13, 1942 INVENTOR HAROLD.A.POSELUND lllll BY Mm) ATTORNEY Patented Mar. 13, 1945 SPRAY GUN Harold A. Roselundg'Toledo,

De Vilbiss CompanyrToldo,

I tion of Ohio Application Mar us, 1942 jseria1rrof se 5a sclaims; (c1.299-140) I V 4 I I the tubular part a, is unthreadedjironi the tube ll'hisinvention relates to spray devices utilizing compressed air for atomization and particularly to such devices in which-the liquid discharged is controlled by a-valveactuatedin one direction by compressed air and in the other by spring means tion of such spray guns. In this appliance how- Ohio assignor to The (Skin, a corpora- 1 and withdrawmfrom the gun bodyt,

v of the needle valve may then be reached; with-Ya ever, applicant has utilized compressed air for maintaining the spray gun in non-sprayingv posiby holding the liquid discharge valve closed. A. principal purpose of the invention is to produce a spray gun that is simplein design and less troublesome than. previous models. .-Anot;her is to produce a spray gun that opens and closes quickly. v i I Inthe drawing, I

Figure 1 is a side elevation of a spray gun em bodying my invention with a portion thereof in section. 1. I

Figure 2- is a vertical section taken on the lines 2--2 of Figure 1. r

Figure 3. is a view oi the forward sideof the finger member for operating the atomizing air valve and av small vertical section of the-gun body taken. on the line 3-3 of Figure l and,

Figure 4 is a rear end view of the spray gun shown in Figure 1. p 1 a q The spray gunillustrated in the-drawing includes a main spray gun body portion l with a spray nozzle 2 and av liquid inlet nipple-3.. The

8 is permanently attached the diaphragm contacting button 9.. The laminated diaphragm In is held, between the clamping ring H and. the outer 3 cap. I 2, which are held together'by cap screws 30.

Air is admitted to the cap! 2 through the nipple [3. This air forces. the diaphragm against the button 9, moving it forwardly with the tubes- I and a compressing the spring it which acts upon the. annular shoulder l'5'of the tube]. The forward movement of the button also acts to propel the needle. valve t-to its sea-tin-the nozzle .2 through spring, l6 which. bears against the enlarged cylindrical section 5; of the needle. The tension developed in this spring holds the needle valve 4 upon its seat.

In case itls desired to remove the needle valve I for replacement purposes, the diaphragm as sembly is removed and the button 9 together with pair of long-nosed pliersand drawn irorn thegun. Thespring ltwill ride along with the needle. valve as it is no longer retained by the 'end of thetubeB.

The tube 1 has lug ll fastened toi-t forward end witha. depending finger part l8..;. Set screw Haholds lu-g t! in placeonthe-endof tube. I. .When the air is released from-the between cap t2 and. the diaphragm l tubular 1 and '8 move rearwardlythroughthe expan-sion action against the button floisprin t (which has also beencompressedbythe-forward movement ofv the button ll) and the expansion of the; spring l4 bearing upon the; shoulder-t5 atthe. end ortube l. otherendor spring. lil -is thrust against the shoulder 20 of the adjustable ring 2| which maybe moved axially through; its threaded connection with the insert 22. The forward end of the adjustable ringh2'l acts. a a stop for the rearward movement of the tube 1 and thereforeby positioning-ring. 2t, the extentof the rearward travel of the needle 4 may be predetermined. The tension oi the spring uporrthe 'adjustable-ringJt acts tohold it in whatever positionit may;be.set. The-, other end or spring M. i thrust against the shoulder 23 of the insert,22-. When through the coaction of springs l4. and, .19 thejoined tuburlar pieces I- and8 aremovedlrearwardly the finger I18 contacts the air valve stem 24 and opens the air valve: controlling the air for ato -In iting"v the liquid which enters the gun body through inlet nipple 2.5. Thestructure of this valve is indicated by dottedlinesin Figure-ls Air released thereby passesiirompassage-.25 around insert 22- into passage 2! by which it reaches the spray gun nozzle. ;After the air-valve is opened the inner'face oithe piece H co tacts the enlarged cylindrical section 5 of the needle 4,

and rearward movement of the; needle- 4 begins and the. liquid is then released. The spray opera,

tion; is thus started. The spray; discharge will continue until. air vis admitted to, the chamber be-v tween the cap l-2 and-the diaphragm: IO- t iorcev the tubular sections forwardly; causingthe needle 4 to seat itself-throu h the. forward propelling action of the; spring Wand theatomizing air to beshut ofi throughnthe release of the air valve stem. m 1' The assembly composed of the cap 12 and :the diaphragm retaining ring I 1 holds the diaphragm H1 in. a-sealed and fixed position;v assembly vjis held together by the cap screws-'30 fastened to the supporting member 29 by cap screws 28. By withdrawing the latter cap screws the assembly may be removed. The member 29 is threaded to the rear end of the insert 22 and is held in position by the adjustable nut 3!. The member 29 may be set forwardly or rearwardly according to the amount of distance it is desired to have the finger l8 ahead of the valve stem 24.

The gun is supported from a rod by means of an interconnecting bracket that ha a bolt (these three parts are not shown) passing through the port 32 in the rearwardly projecting boss 33 of cap 12. The main body of the gun may be removed by withdrawing cap screws 28. Thi does not disturb the clamping arrangement by which the diaphragm assembly is fastened to the supporting rod, nor the seal of the diaphragm as it remains locked between the ring II and the cap I 2. V

This arrangement provides an automatic spray gun in which the diaphragm controlling the needle is a part of a sub-assembly from which the main spray gun body may be disconnected. A standard spray gun and various types or sizes of diaphragm or piston units may be used interchangeably.

By having the air acting upon the diaphragm upon the side opposite to that which contacts the needle valve opening elements, there is no need of providing sealing means around the elements to prevent air escaping from the needle side of the diaphragm. This is a common source of trouble among other spray guns of the automatic type. Leaks of air at this point are objectionable as they may adversely afiect the operation of the spray gun by lowering the air pressure and thus slowing up the piston or diaphragm movement.

It is to be understood that the form of my invention, herewith shown and described, is to be taken' as a preferred example of the same, and that various changes in the shape, size and arrangements of parts may be resorted to, without departing from the spirit of my invention, or the scope of the following claims.

For instance the spray gun shown and described herein has a diaphragm for operating the liquid discharge needle valve. A piston would serve substantially as satisfactorily, and I therefore wish it understood that a piston and a diaphragm should be considered equivalent as far as this invention is concerned and that reference to either in'the claims should be broadly interpreted.

Having thus described my invention I claim:

1. In an automatic spray gun, a liquid discharge nozzle, a needle valve for controlling the flow of liquid from the nozzle, a rearwardly fac ingseat in the nozzle, a needle motivating member of tubular shape surrounding the rear end of the needle and extending beyond it, an air actuateddiaphragm, a diaphragm contacting portion on the needle motivating member against which the forward face of the diaphragm bears, spring means opposing the forward movement of the motivating member and moving the member and the needIe away from theneedle seat when compressed air is not applied against the diaphragm, and adjustable means concentric with the motivating member positioned to stop the latter after a predetermined rearward movement.

2. In an automatic spray gun, a spray gun body, a spray discharge nozzle, liquid and air passages leading to the nozzle, a needle: valve seating in the nozzle to control the flow of liquid,- an air valvefor controlling the discharge of air adjacent and parallel to the liquid needle valve, a rearward extension of the gun body, an air chamber in the extension, a diaphragm forming the forward wall of the chamber, means for supplying compressed air to the chamber, a tubular member surrounding the rear end portion of the liquid needle and having a button shaped end contacting the diaphragm, a spring within the gun body surrounding the tubular member and bearing against a forward facing shoulder of the member and a normally fixed rearwardly facing shoulder to impel the member rearwardly, an enlarged portion on the needle within the tubular member, an inwardly extending flange on the forward end of the tubular member in line to engage the enlarged portion of the needle and to move the latter rearwardly, and a laterally extending finger secured to the tubular member in line with the air valve and engaging it when the tubular member is moved rearwardly,

3. In an automatic spray gun, a body member, a liquid discharge nozzle, a, needle valve for controlling the flow of liquid froln the nozzle, a rearwardly facing seat for the needle valve within the nozzle, a needle motivating member positioned in surrounding-relation to the rear portion of the needle, spring means so supported and positioned that it bears against a normally fixed rearwardly facing shoulder within the body member and a forwardly facing surface of the motivating mem her to move the member rearwardly, a forwardly facing lateral shoulder on the needle, an inwardly offset portion of the motivating member engaging the forwardly facing lateral shoulder on the needle and moving the needle from its seat when the motivating member is moved rearwardly by the spring means, an air actuated diaphragm associated with the rear end of the motivating means, means to supply air on the rear side of the diaphragm to force it and the motivating member toward the nozzle, and a compressible member positioned between a forwardly facing surface of the motivating member and a rearwardly facing surface of the needle to urge the needle forwardly toward its seat in the nozzle.

4. In an automatic spray gun using air for atomization, a body member, a liquid discharge nozzle at the forward end of the body member, a needle valve for controlling the flow of liquid from the nozzle, a rearwardly facing seat for the needle within the nozzle, a tubular needle motivating member positioned in surrounding relation to the rear portion of the needle, spring means so supported and positioned that it bears against a normally fixed rearwardly facing shoulder upon the body member and a forwardly facing shoulder of the motivating member to move the member rearwardly away from the nozzle, an annular enlargement on the needle, an offset portion of the motivating member in line to engage the annular enlargement on the needle when the motivating member is moved rearwardly by the spring means, an air valve, positioned adjacent the motivating member, for controlling the flow of atomizing air to the nozzle, a laterally extending finger on the motivating member positioned to contact and open the air valve when the motivating member is moved rearwardly by the spring means, ,a diaphragm associated with the rear end of the motivating member, means to actuate the diaphragm by applying compressed air to the rear surface thereof whereby the motivating member is moved forwardly, and spring means positioned between a forwardly facing surface of the motivating member and a rearwardly facing spring thrust receiving surface on the needle to urge the needle ahead of the motivating member toward the nozzle.

5. In an automatic spray gun utilizing air for atomization of the liquid to be sprayed, a main body member, a liquid discharge nozzle at the forward end of the body member, a needle valve seating in the nozzle for controlling the flow of .liquid therefrom, a reciprocable needle motivating members having an axially extending interior chamber, said chamber being closed at its rear end and having a small bore at its forward end through which the needle extends, spring means supported upon a forwardly facing surface within the chamber and thrusting against a rearwardly facing surface of the needle to urge it forwardly toward its seat, a radially enlarged portion on the needle within the chamber spaced slightly from the interior forward wall of the chamber and against which the interior forward wall surrounding the bore strikes when the needle motivating member is moved rearwardly to withdraw the needle from its seat, a passage through i the spray gun body member for the atomizing air, a reciprocable air valve adjacent the needle motivating means for controlling theflow of air through the passage, a contact means extending from the motivating member to the air valve, secondary spring means with one end resting against a support fixed to the gun body and With the other thrust against a surface of the motivating member to urge it axially into and hold it in one position, and means responsive to air pressure and associated with the motivating member for moving it axially in opposition to the action of the secondary spring means into an alternate position, when the motivating member is in one of said positions the needle is held to its seat in the nozzle and when said member is in the other position the needle is withdrawn from its seat and the air valve is opened.

6. In an automatic spray gun, a main ,bodytherefrom, a reciprocable needle. motivating.

member having an axially extending interior chamber, said chamber being closed at its rear end and having a small bore at its forward and through which the needle extends, spring means supported upon a forwardly facing surface within the chamber and thrusting against a rearwardly facing surface of the needle to urge it forwardly toward its seat, a radially enlarged portion on the needle within the chamber against which the interior forward wall of the chamber surrounding the 'bore strikes when the needle motivating member is moved rearwardly to withdraw the needle from its seat, an air valve for controlling the flow of atomizing air positioned adjacent and substantially parallel to the motivating member,.

a laterally extending finger on the motivating member positioned to contact and open the air valve when the motivating member is moved rearwardly, secondary spring means with one end resting against a fixed support upon the gun body and with the other thrust against the motivating member to move it axially into and hold it in one position and means responsive to air pressure and connected to the motivating member for moving it axially in opposition to the action of the secondary spring means into an alternate position, when the motivating member is in one of said positions the needle is held to its seat in the nozzle and when said memberis in the other position the needle is Withdrawn from its seat and the air valve is opened.

HAROLD A. ROSELUND, 

